Ingredients

• 1 1/2 tablespoons cumin seeds
• 1 teaspoon black mustard seeds*
• 1/2 teaspoon ground coriander
• 1/2 teaspoon ground turmeric
• Pinch of cayenne pepper
• Pinch of fennel seeds
• 1 tablespoon minced peeled fresh ginger
• 1/4 cup plus 1 tablespoon canola oil
• 2 to 3 white onions, chopped (4 cups)
• 2 1/2 pounds red yams or sweet potatoes, grated (4 cups)
• 5 tablespoons whole wheat flour
• 1 large egg, beaten
• 1 1/2 teaspoons kosher salt
• 1 cup plain yogurt
• 1/2 cup chopped scallions, white and green parts, for garnish

Instructions

1. Combine the cumin seeds, mustard seeds, coriander, turmeric, cayenne, fennel seeds, and ginger in a small bowl. Stir well to blend.
2. In a large sauté pan set over medium heat, heat the 1/4 cup oil. Add the onions and cook, stirring occasionally, until they are caramelized to a golden brown, 10 to 15 minutes. Reduce the heat to low and add the spice mixture. Cook for 1 to 2 minutes to toast the spices. Transfer the mixture to a bowl. Add the yams, flour, egg, and salt, and mix well to combine. Form the mixture into cakes that are about 3 inches in diameter and 1/4 inch thick, and put them on a baking sheet.
3. Set a skillet over medium-low heat and add the remaining 1 tablespoon oil. Working in batches, sauté the cakes for 3 to 4 minutes on each side. They are done when they are a crispy golden brown and the sweet potato is cooked through.
4. Serve warm, topped with the yogurt and scallions.